Immanuel Kant was by no means a Catholic philosopher, but he still wrote some things helpful for Catholics. Consider, for example, Kant’s discussion early in the Grounding for the Metaphysics of Morals on the purpose of life.
What is the purpose or goal of life for a human being, a rational animal? According to Kant, it isn’t to be happy. He offers the following paradox as evidence for this:
“The more a cultivated reason devotes itself to the aim of enjoying life and happiness, the further does man get away from true contentment.” (Grounding, trans. J. Ellington, First Section)
Put differently, constantly questioning yourself as to whether you are “happy” is a poisonous endeavor. It tends to make you unhappy. And this is a problem, as one of my students pointed out in class yesterday, because we never stop thinking. But that does not mean we are doomed as humans to constantly question our happiness and constantly make ourselves unhappy. Rather, As Kant will go on to argue, we should spend most of our time thinking about a different question: what must I do? That is to say, the true purpose of human life is not so much to be happy as it is to be good. Goodness is the goal of human existence.
There is nothing inherently religious about this. Kant writes merely as a philosopher, as someone using reason to think about what is true of human life. However, Kant’s conclusion that we are called to goodness is also a truth expressed in various ways by the Church. There is Psalm 4, prayed every Saturday night by the Church: “Make justice your sacrifice and trust in the Lord.” Or one could invoke the famous quote from Mother Teresa: “We are not called upon to be successful, but to be faithful.” And for American Catholics, we should never forget that magisterial line from the old Baltimore Catechism on the purpose of life: “God made me to know Him, to love Him, and to serve Him in this world, and to be happy with Him forever in Heaven.”
If there is any difference between Kant and the Church on this matter, it can be seen in the second half of that line from the Baltimore Catechism. The Church never gives up on happiness. Rather, happiness remains the ultimate, final goal of human life. But in this earthly existence, we are to direct ourselves to goodness–to faith and good works. Or to put it in a way closer to the style of Blessed John Paul II, the purpose of this earthly life is to make a gift of oneself.